The STM32 Makes For A Cheap DIY USB Soundcard

Soundcards used to be giant long 8-bit ISA things that would take up a huge amount of real estate inside a desktop computer. These days, for most of us, they’re baked into the motherboard and we barely give them a second thought. [Samsonov Dima] decided to whip up a cheap little sound card of their own, however, built around the STM32.

The soundcard is based specifically on the STM32F401. readily available on the “Green Pill” devboards. A digital-to-analog converter is implemented on the board based on two PWM timers providing high-quality output. There’s also a simulated software sigma delta ADC implemented between the audio streaming in via USB and the actual PWM output, with some fancy tricks used to improve the sound output. [Samsonov] even found time to add a display with twin VU meters that shows the audio pumping through the left and right channels.

Without test gear on hand, we can’t readily quantify the performance of the sound card. However, as per the Youtube videos posted, it appears more than capable of recreating music with good fidelity and plenty of fine detail.

If you need a cheap, simple USB sound card that you can hack away on, this might be the one for you. If you need something more suitable for a vintage PC, however, consider this instead. Video after the break.

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Character VFD Becomes Spectrum Analyzer

These days, streaming services are a great way to listen to music or podcasts on your computer or on the go. However, they lack one feature of the MP3 players and streamers of old: visualizations! [mircemk] is a fan of those, and has built a hardware spectrum analyzer that pumps with the music.

The build relies on a 20×2 character VFD display that looks great, with high brightness and excellent contrast. It can be easily driven from a microcontroller, as it has a controller on board compatible with the typical HD44780 command set. On Arduino platforms, this means the display can easily be driven with the popular LiquidCrystal library.

The Arduino Nano inside takes in the audio signal via its analog inputs. It then processes the audio with the fix_fft library, which runs a Fast Fourier Transform in order to figure out the energy level of each frequency bin in the audio spectrum for both the left and right channels. This data is then sent to the screen for display. It’s impressively fast and smooth, with the display dancing along with the beat nicely as [mircemk] tests it out with some tunes.

If it looks familiar, it’s because it’s an updated version of a prior project from [mircemk]. We saw it previously as a VU meter that pulsed with the beat, an altogether simpler visualization but still a cool one. Video after the break.

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Put Another Dime In The Jukebox

We don’t always acknowledge it, but most people have an innate need for music. Think of all the technology that brings us music. For decades, most of the consumer radio spectrum carried music. We went from records, to tape in various forms, to CDs, to pure digital. There are entire satellites that carry — mostly — music. Piracy aside, people are willing to pay for music, too. While it isn’t very common to see “jukeboxes” these days, there was a time when they were staples at any bar or restaurant or even laundrymat you happened to be in. For the cost of a dime, you can hear the music and share it with everyone around you.

Even before we could record music, there was something like a jukebox. Coin-operated machines, as you’ll recall, are actually very old. Prior to the 1890s, you might find coin-op player pianos or music boxes. These machines actually played the music they were set up to play using a paper roll with holes in it or metal disks or cylinders.

Early Days

That changed in 1890 when a pair of inventors connected a coin acceptor to an Edison phonograph. Patrons of San Francisco’s Palais Royale Saloon could put a hard-earned nickel in the slot and sound came out of four different tubes. Keep in mind there were no electronic amplifiers as we know them in 1890. Reportedly, the box earned $1,000 in six months.

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Show Us Your Odd Inputs And Peculiar Peripherals!

Just as the Jedi youngling would have to build their light saber, so is it a rite of passage for a true geek to build their own computer interfaces. And nothing makes a personal computer more personal than a custom keyboard, a bespoke mouse, an omnipotent macropad, a snazzy jog wheel, or a fancy flight yoke.

In this contest, we encourage you to make your strangest, fanciest, flashiest, or most custom computer peripherals, and share that work with all the rest of us. Wired or wireless, weird or wonderful, we want to see it. And Digi-Key is sponsoring this contest to offer three winners an online shopping spree for $150 each at their warehouse! More parts, more projects.

Make It Yours

Anyone can just go out an buy a keyboard, but if you want a custom ergonomic keyboard that’s exactly fit to your own two hands, you probably have to make one with your own two hands. And if you an engraved brass mouse, well, you’ve got some engraving to do — Logitech ain’t gonna make one for you. Maybe you only type in binary, or maybe you need a keyboard for some alien language that has 450 individual letters. Or maybe the tiniest keyboard ever? You’ve got this. Continue reading “Show Us Your Odd Inputs And Peculiar Peripherals!”

PSP Turned Robot Remote With Custom Software

There’s no question that Sony’s PlayStation Portable (PSP) was an impressive piece of hardware when it was released in 2004, but for all its technical wizardry, it wasn’t able to shake Nintendo’s vice-like grip on the handheld market. Perhaps that explains why we still see so many nostalgia-fueled hacks for Nintendo’s Game Boy and Dual Screen (DS) systems, while PSP hacks tend to be few and far between.

But looking at projects like this one that turn the PSP into a capable robot controller (video, embedded below) we can’t help but wonder if the community has been missing out. Thanks to an open source software development kit for the system, [iketsj] was able to write a WiFi controller program that can be run on any PSP with a homebrew-compatible firmware.

The other side of the equation is a simple robot powered by an ESP8266. To take control of the bot, the user connects their handheld to the WiFi network being offered by the MCU and fires up the controller application from the main menu. It’s all very slick, and the fact that you don’t need to make any modifications to the PSP’s hardware is a huge plus. From the video after the break we get the impression that the remote software is pretty simplistic in its current form, but we imagine the only really limitations are how good you are at writing C code for what by today’s standards would be considered a fairly resource constrained system. We’d love to see that widescreen display lit up and showing live first-person video from the bot’s perspective.

Many of the PSP hack’s we’ve seen over the years have been about repurposing the hardware, or in some cases, replacing the system’s internals with something raspberry flavored. Those projects have certainly been interesting in their own ways, but we really like the idea of being able to push a largely stock system into a new role just by writing some custom code for it.

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Handling Bulk Material: Why Does My Cat Food Get Stuck?

Bulk material is stuff handled ‘in bulk’. One LEGO piece is a brick but 1,000 poured into a bag is bulk material. Corn starch, sand, flour, powder-coat powder, gravel, cat food, Cap’n Crunch, coins, screws, Styrofoam beads, lead shot, and gummy worms are bulk materials.

Applications abound where you need to move stuff in bulk. Selective sintering 3D printers, animal feeders, DIY injection molders, toner based PCB makers, home powder coating, automatic LEGO/domino/whatever sorters or assemblers, automated gardeners, airsoft accessories – handling bulk material is part of hacking. College science classes cover solids and liquids, but rarely bulk materials.

Most hackers just pray it works and tap the bin when it doesn’t. Industry does better, but the slang term “bin rash”, the long term result of tapping a 300 ton bin with sledgehammers (video),  shows they don’t get it right all the time either. At the same time, it’s a fun area you can experiment with using kitchen items. So come along with us for a short series on the basics of bulk material handling. Continue reading “Handling Bulk Material: Why Does My Cat Food Get Stuck?”

Point Out Pup’s Packages With This Poop-Shooting Laser

When you’re lucky enough to have a dog in your life, you tend to overlook some of the more one-sided aspects of the relationship. While you are severely restrained with regard to where you eliminate your waste, your furry friend is free to roam the yard and dispense his or her nuggets pretty much at will, and fully expect you to follow along on cleanup duty. See what we did there?

And so dog people sometimes rebel at this lopsided power structure, by leaving the cleanup till later — often much, much later, when locating the offending piles can be a bit difficult. So naturally, we now have this poop-shooting laser turret to helpfully guide you through your backyard cleanup sessions. It comes to us from [Caleb Olson], who leveraged his recent poop-posture monitor as the source of data for where exactly in the yard each deposit is located. To point them out, he attached a laser pointer to a cheap robot arm, and used OpenCV to help line up the bright green spot on each poop.

But wait, there’s more. [Caleb]’s code also optimizes his poop patrol route, minimizing the amount of pesky walking he has to do to visit each pile. And, the same pose estimation algorithm that watches the adorable [Twinkie] make her deposits keeps track of which ones [Caleb] stoops by, removing each from the worklist in turn. So now instead of having a dog control his life, he’s got a dog and a computer running the show. Perfect.

We joke, because poop, but really, this is a pretty neat exercise in machine learning. It does seem like the robot arm was bit overkill, though — we’d have thought a simple two-servo turret would have been pretty easy to whip up.

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